1. Field of the Invention
The present invention generally relates to a low noise amplifier with multiple inputs and multiple outputs.
2. Background Art
Satellite set-top boxes (STB) are increasingly being designed with multiple tuners, making them capable of receiving more than one program at a time. In addition, satellite STBs are increasingly being designed with multiple inputs, to permit reception of additional channels that will not fit within the conventional satellite intermediate frequency (IF) band (950-2150 MHz). Often, the STB must route these multiple inputs to the multiple tuners with some form of switching function, to allow each tuner to receive all channel bands.
At present, satellite STBs use complex front ends designed with discrete transistors, diodes and filters to perform these functions. These discrete front ends have limited performance and require large amounts of area on the STB printed circuit boards (PCBs). This is because complex circuits that would improve the performance, such as automatic gain control (AGC) and differential amplifiers are prohibitively large and expensive when implemented with standard discrete components.
In addition, discrete RF design is a difficult and time-consuming process. Given the short life cycles of consumer electronic products, a lengthy and error-prone design process may be unacceptable.
What is necessary is a radio-frequency integrated circuit (RFIC) that incorporates splitting, switching, AGC, and filtering functions for multi-input/multi-tuner satellite STBs.